Fluidic brake control system having safety and overspeed control means for railroad trains

ABSTRACT

A fluidic brake control system for a railway train interlocked with the conventional airbrake control system in which both &#39;&#39;&#39;&#39;safety&#39;&#39;&#39;&#39; and &#39;&#39;&#39;&#39;overspeed&#39;&#39;&#39;&#39; control of a bistable element is provided to control interface devices capable of effecting either a release of the train brakes or producing a penalty brake application. A safety control circuit employs a multistage binary counter to provide timing and sequencing whereby the operator is required to periodically acknowledge a counter controlled warning signal by resetting the counter to prevent occurrence of the impending penalty which is imposed by reason of the counter proceeding to its final stage. In the event the counter reaches its final stage due to the warning signal not being acknowledged in the prescribed manner, the bistable element is triggered to initiate and latch in the penalty until conditions of a logic circuit are satisfied to reset the bistable element which is accordingly conditioned to effect a release of the brakes. The overspeed control circuit employs timing means separate from the counter but employs the counter to initiate the penalty by setting its final stage to the penalty state irrespective of the normal counter sequence.

United States Patent [72] Inventors Ronald A. Sarbach Columbus, Ohio;Shantilal N. Shah, Pittsburgh, Pa. [211 App]. No. 875,805 [22] FiledNov. 12, 1969 [45] Patented Nov. 30, 1971 [73] Assignee Westinghouse AirBrake Company Wilmerding, Pa.

[54] FLUlDlC BRAKE CONTROL SYSTEM HAVING SAFETY AND OVERSPEED CONTROLMEANS FOR RAILROAD TRAINS 13 Claims, 1 Drawing Fig.

[52] US. Cl 303/19, 303/20, 340/279 [51] lnt.Cl B60t 7/14, B60t 13/66[50] Field of Search 137/599; 235/201; 303/19, 20; 340/279 [56]References Cited UNITED STATES PATENTS 3,177,481 4/1965 .loy et al340/279 3,312,508 4/1967 Keller et a1. 303/19 3,476,442 11/1969 Sarbach303/19 Primary ExaminerMilton Buchler Assistant Examiner-Stephen GvKunin Attorney-Ralph W Mclntire, .lr.

ABSTRACT: A fluidic brake control system for a railway train interlockedwith the conventional airbrake control system in which both safety andoverspeed control of a bistable element is provided to control interfacedevices capable of effecting either a release of the train brakes orproducing a penalty brake application, A safety control circuit employsa multistage binary counter to provide timing and sequencing whereby theoperator is required to periodically acknowledge a counter controlledwarning signal by resetting the counter to prevent occurrence of theimpending penalty which is imposed by reason of the counter proceedingto its final stage. In the event the counter reaches its final stage dueto the warning signal not being acknowledged in the prescribed manner,the bistable element is triggered to initiate and latch in the penaltyuntil conditions of a logic circuit are satisfied to reset the bistableelement which is accordingly conditioned to effect a release of thebrakes, The overspeed control circuit employs timing means separate fromthe counter but employs the counter to initiate the penalty by settingits final stage to the penalty state irrespective of the normal countersequence.

PATENTED unvao l97| INVENTOR. RONALD A. SARBACH BY SHANTILAL N. SHAH KW,474M}, ATTORNEY FLUIDIC BRAKE CONTROL SYSTEM HAVING SAFETY AND OVERSPEEDCONTROL MEANS FOR RAILROAD T AlNs BACKGROUND OF THE INVENTION Therailroad industry had, from its inception, been dedicated to a policy ofassuring that precautionary measures are taken to maintain stringentsafety standards in all aspects of its operation. In keeping with thispolicy, locomotive brake equipment, in freight as well as passengerservice, has traditionally been designed to include a penalty brakecontrol system, one concept of which requires either continual orperiodic acknowledgment by the engineer to indicate his alertness andwell being in order that he may continue to maintain control of thetrain. Maintaining a foot valve pedal in a depressed condition oralternately depressing and releasing the foot valve pedal are specificrequired functions associated with such a penalty brake control systemto monitor the engineer's condition. The latter function is intended toovercome the possibility of the engineer defeating the purpose of thesystem by weighing down the foot valve with some object other than thefoot. In the event the operator, due to his being incapacitated by hisown volition, fails to fulfill the prescribed control procedure, thebrake control system automatically operates to produce a penalty brakeapplication to safely bring the train to a halt. The existing systems,with their associated piping, while being relatively reliable inoperation, are quite bulky, costly and require periodic maintenance.

Other systems based on surveillance of the operator have been attemptedin addition to the acknowledgement type, wherein electronic means areemployed to monitor movements made by the engineer in the process ofperforming his normal-operating functions. Being fragile by nature andcomplex by necessity of design, it becomes immediately apparent thatsuch systems are inherently unreliable, especially when subjected tosuch extreme environmental conditions as are known to exist in railroadservice. Electronic systems, in addition to their high-initial cost,prove not only difficult to maintain in an operative condition, but areexpensive to service.

Recently, the development of small fluid pressure control devices thatuse no moving parts other than the fluid itself has led to completelynew concepts in fluid control concepts so different that a distincttechnology known, for the lack of a more descriptive name, as fluidicshas emerged. Although primarily employing the fluid-dynamic interactionphenomena which for the most part encompasses devices commonly referredto as pure fluid elements, the fluidic technology does not rule out useof spool valves, ball valves or other miniature control elements inwhich the moving mass is so small that response time of the device isnot significantly affected. Being fluid pressure in nature, even thoughfluid pressures employed with fluidics are typically low, this newtechnology appears to lend itself well to application with fluidpressure brake control systems, particularly when employed in the areaof the locomotive where a ready source of fluid supply is available.

SUMMARY OF INVENTION It is the object of the present invention toprovide a new and improved penalty brake application control circuitadapted to be interlocked with the conventional automatic brake valvecontrol of the power brakes and comprising pure fluid devices whereinsafety and overspeed control is provided to assure safe operation of atrain with a low-cost, compact package which is highly reliable andrelatively free of maintenance.

It is another object of the invention to provide a cycling type controlof the safety control portion of the penalty brake application circuit,requiring only momentary actuation of a control mechanism periodicallyto forestall initiation of a penalty brake application.

In the attainment of the above objects, a four-stage binary counter isprovided to obtain a binary output signal. A square wave input signal isgenerated by a fluidic oscillator to drive the counter. An interlockvalve device is arranged so that under normal conditions, communicationis established therethrough to accommodate normal brake valve control ofthe automatic brakes by variation of a control pressure and underpenalty conditions, communication is established therethrough to reducethe control pressure and thereby cause an automatic brake application. Afluidic flip-flop device monitors the counter fourth stage to pilot afluidic lowto high-pressure relay which in turn positions the interlockvalve device to initiate the penalty.

In a safety control circuit, a predetermined duration before the penaltycondition is imposed, a warning whistle is sounded to apprise theengineer of the impending penalty. A fluidic AND gate interposed betweenthe counter and a second fluidic lowto high-pressure relax responds tothe counter output signals to pilot the relay to initiate sounding ofthe warning whistle.

In order to forestall the impending penalty, the operator mustacknowledge the warning whistle within the alotted time duration beforethe counter reaches the penalty stage. This can be accomplished byactuating a valve device adapted to pressurize the counter reset ports,thus resetting the counter stages. Since the counter is continuouslycycling, periodic acknowledgement is required on the part of theengineer to forestall the penalty and indicate his alertness andwell-being. The penalty may also be forestalled through fluidic logiccircuits which also function to reset the counter whenever the operatorsbrake valve device is moved into suppression position or any timeapproximately 25 p.s.i. locomotive brake cylinder pressure exists.

Operating in conjunction with the safety control circuit is an overspeedcontrol circuit having separate timing means whereby an electromagnetvalve device monitors the locomotive engine speed to control a fluidicNOR gate which is adapted to set the counter to its fourth stage,indicating a penalty condition when the engine speed exceeds apredetermined limit.

The invention will be better understood from the following more detaileddescription which, when considered with the single FIGURE drawingshowing a schematic representation of a fluidic penalty brake controlcircuit comprising the invention, will make apparent other objects andadvantages to be gained.

DESCRIPTION Referring now to the drawing, there is shown a fluidicsafety and overspeed control circuit, the outputs of which pilot aninterlock valve device 1 which is illustratively shown as a twoposition, fluid pressure operated, spool valve device. Interlock valve 1is employed for the purpose of porting high-fluid pressure to effectcertain prescribed function, as hereinafter described, in response topressure signals effective at pilot valves 2 or 3 as derived from thealternate high-pressure outputs of a digital lowto high-pressure fluidicinterface device 4. Thus, one or the other of the pneumatic pilotportions 2 and 3 of interlock valve 1 is pressurized placing the spoolvalve in either a first or a second position. In the first or normalposition, as shown, an equalizing reservoir control volume 5 isconnected via the spool valve and line 6 to a conventional locomotivebrake valve device from which it is changed by a source of regulatedcontrol pressure provided by the locomotive brake valve device and iscut off from a second volume 7 (typically known as the reductionlimiting reservoir) which is connected to atmosphere via a one-way checkvalve 8. In the second or penalty position, the spool valve cuts oflcharging of the equalizing reservoir volume 5 which is consequentlyconnected to the volume 7 into which the control pressure equalizes toeffect a predetermined reduction in control reservoir pressure dependentupon the size of volumes 5 and 7. As is well known in the air brake art,a reduction of equalizing reservoir control pressure at the locomotivebrake valve device results in a corresponding reduction in brake pipepressure throughout the train to cause the locomotive and train brakesto apply accordingly. It is apparent, therefore, that by actuatinginterface device 4 to a position in which the interlock valve 1 isforced to its second position at the time a penalty condition exists, asdetected by either the safety or overspeed circuits, as will hereinafterbe explained, a predetermined penalty brake application willautomatically be imposed.

A lowto high-pressure interface valve device 9, similar to interfacedevice 4 and having its connected output in series with the one outputthereof, is provided to control the sounding of a warning whistle 10,which occurs periodically to apprise the engineman of an impendingpenalty condition which, in order to forestall or suppress, requires hisacknowledgement in any one of certain prescribed ways hereinafterexplained.

Interface devices 4 and 9 are each comprised of a high-pressure portion11 and a fluidic pilot portion 12 in the form of a conventional purefluid OR/NOR gate and are commercially available. Although not shown indetail, the high-pressure portion comprises a piston actuator to whichone end of a ported rotor is movably connected so as to effectcommunication between a source of high-fluid pressure supply at port 13and one or the other of output ports 14 and 15 associated with interfacedevice 4, and output ports 16 (which is plugged) and 17 associated withinterface device 9 depending upon the transverse position of the pistonactuator. Being conventional in design, the OR/NOR gate comprising thepilot portion 12 includes a preferred NOR-output leg 18 and an OR-outputleg 19 adapted to alternately pressurize opposite sides of the pistonactuator from a regulated source of supply pressure at the power inputof the device in accordance with the presence or absence of a pressuresignal at control port 20 of the respective OR/NOR gates. As the pistonactuator is forced to either of its extreme transverse positions inresponse to the OR/NOR gate output, the rotor is consequently positionedto connect a source of high-pressure supply at port 13 to one or theother of outputs l4 and 15 associated with interface device 4, and ports16 and 17 associated with interface device 9. The small size of thecomponents as well as the absence of sealing elements on the pistonactuator, combined with the wiping or shear-seal action of the rotorwith respect to the housing, permits low friction, low-inertia operationwith reliable switching of the high-pressure output signals inaccordance with the low-fluidic pressure state control signals.

The timing and sequencing functions of the safety control circuit areprovided by a counter of any conventional type. Preferably, the timingand sequencing functions are embodied in a four-stage binary counter 21which forms the heart of the system. The counter is driven by a fluidicfree-running multivibrator or oscillator 22 capable of generating asquare wave fluid pressure signal. The counter stages, as hereinafterdescribed in detail, sequentially divide the input pulse from theoscillator in a binary fashion. Details of the oscillator 22 are notshown in the drawing due to the various standard configurationscommercially available. However, the circuit configuration could, as anexample, comprise a bistable flip-flop device arranged arranged so thatits one control port is maintained pressurized to bias the supply streamtowards the preferred output leg which is connected into a volume andthe opposing control port. When the pressure in the volume builds upsufficiently to overcome the bias control signal at the one control pot,the supply stream is switched out of the preferred output where itremains until the volume pressure is dissipated below the bias pressure,at which point, the supply is returned to the preferred output. Tappingoff one of the outputs, therefore, produces a square wave, the frequencyof which is determined by the time required to charge and discharge thevolume above and below the bias level.

Each stage of the binary counter 21, as shown diagrammatically andindicated by the reference numerals 23, 24, 35 and 26, may comprise afluidic differentiator or one-shot circuit, not shown, to detect apositive going pulse and produce a short duration spike" output andfurther comprises fluidic flip-flop circuitry, not shown, fabricatedfrom two flip-flops, not shown, interconnected in a back-to-backconfiguration, which flip-flop circuit is triggered from the one-shot toproduce the output signal at that particular stage. Cascading the stagesby connecting the output of the previous stage to the differentiator ofthe following stage produces a binary counter with as many stages asdesired. Monitoring the output signal of each stage at ports 27, 38, 29and 30 gives the binary count sequence upon which the fluidic circuittiming and control functions are predicated. Port 31 at each stage ofthe counter is provided to reset the counter stages to their originalstate whenever a pressure signal is produced thereat by way of line 32.At the set input of the fourth stage 26 is a port 33 which, whenpressurized, immediately sets the fourth stage to its connected output30.

Connected to the counter second and third stage output ports 28 and 29are the control ports 34 and 35 of a pure fluid AND-gate 36. Beingconventional in design, it includes a power port to which is supplied aregulated source of fluidic pressure, a preferred NAND-output leg 37 anda connected AND-output leg 38, as well as the control ports 34 and 35.Concurrent pressurization of the control ports enables the device, inwhich stage the output leg 38 is pressurized from the power input andthe output leg 37 is depressurized. In the disabled state, when one orboth the control signals are absent, the opposite logic conditions existat the output legs. Leg 38 is connected to control port 20 of interfacedevice 9 whereby sounding of warning whistle 10 is controlled inaccordance with the presence or absence of pressure at the AND-gateoutput leg 38 as dictated by timing of the counter.

A pure fluid flip-flop device 39 is provided to control initiation of apenalty brake application by controlling operation of interface 4 whichin turn controls interlock valve 1. A control port 40 of flip-flop 39 issubject to the presence or absence of a fluid pressure signal outputport 30 of counter stage 26. Being conventional in design, flip-flop 39comprises a power input at which is maintained a regulated source offluidic pressure, a pair of output ports 41 and 42 pressurized inaccordance with the selective pressurization of control port 40 and anopposing control port 43 respectively. By virtue of inherent memory dueto its bistable characteristic, the flip-flop device will maintain thepressurized output in a pressurized condition even though the actuatingone of the control ports is thereafter depressurized, and until theopposite control port becomes pressurized.

As mentioned heretofore, pressurization of reset ports 31 at each stageof the counter by way of line 32 results in each stage of the counterbeing reset to its initial state from where the count sequence isstarted. Several ways of generating this pressure signal are availableto the operator, one of which requires the momentary actuation of a pushbutton actuated, three-way valve device 44 adapted to charge a volumereservoir 45 from a source of high pressure in its normal deactuatedposition, as shown. When valve device 44 is actuated by reason of theoperator depressing the push button operator, fluid under pressure involume 45 is connected to line 32 and to the reset ports 31 at eachcounter stage. The counter is also reset any time locomotive brakecylinder pressure is developed above a predetermined value(approximately 25 psi). A pure fluid OR-gate 46 provides this functionby sensing brake cylinder pressure supplied to a control port 47 by wayof a pressure restrictor. Being conventional in design, OR-gate 46comprises a power input to which is supplied a regulated source offluidic pressure, an OR-output leg 48 having communication with line 32,a preferred NOR-output leg 49 having communication with atmosphere, anda control port 50 in addition to control port 47. The OR-output leg 48is pressurized and the NOR-output leg 49 depressurized when either oneor both control ports are pressurized. Conversely, NOR-leg 49 ispressurized and OR-leg 48 depressurized when the device assumes itspreferred state due to neither control port 47 nor 50 being pressurized.

Still another means of resetting the counter is available by placing thelocomotive brake valve device in suppression position. This condition issensed by the pressure state condition at control port 51 of aconventional pure fluid flip-flop device 52, the one output leg 53 ofwhich is connected to the control port 50 of OR-gate 46 to effect thecounter reset function. An opposing control port 54 is provided to causethe flip-flop to switch to its opposite state in which an output leg 55is pressurized in accordance with pressurization of the control port 54by way of a pressure restrictor when the brake valve device is moved torelease position.

in accordance with releasing a penalty initiated brake application, aswill hereinafter be more fully explained, a pure fluid AND-gate 56 isprovided, being conventional in design similar to AND-gate 36. AND-gate56 is subject at its one control port 57 to the pressure state signaleffective at output 55 of flip-flop 52. Control of the regulated fluidicsource of supply pressure to either a preferred output leg 58 havingcommunication with the atmosphere or to a connected output leg 59 isafforded by the combined pressure state signals effective at controlport 57 and a second control port 60. The pressure state of theconnected output leg 59 is monitored by the control port 43 of flip-flopdevice 39 to reset the flip-flop from its penalty state when the outputsignal at port 30 of counter stage 26 disappears.

A pure fluid flip-flop device 61 is provided to control the pressurestate at the control port 60 of AND-gate 56 and thus influence thepenalty reset function of flip-flop 39. Being conventional in design,flip-flop device 61 comprises a power input to which a regulated sourceof fluidic pressure is maintained for supplying an output leg 62 havingcommunication with the atmosphere or an output leg 63 connected tocontrol port 60 of AND-gate 56 in accordance with the pressure stateconditions effective at a control port 64 or at opposing parallelcontrol ports 65 and 66 respectively. The pressure state conditioneffective at control port 64 is dependent upon the state of flip-flop52, its output 53 being connected to control port 64 by way ofa delaymeans 67. Connecting output leg 53 to control port 64 with a longer thannormal length of tubing wound in the shape of a coil for the sake ofcompactness will conveniently provide the delay means for a purposewhich will hereinafter become apparent.

The overspeed portion of the control circuit is arranged to operate inconjunction with the above-described safety control portion andcomprises an electromagnetic type, three-way valve device 68, a volume69 into which fluid under pressure is normally charged from ahigh-pressure source, a warning whistle 70 adapted to be sounded inresponse to the fluid pressure in volume 69 at the time theelectromagnetic valve is actuated, and a pure fluid NOR-gate 71, alsosubject at its control port 72 to the fluid pressure effective in volume69. in the enabled state of NOR-gate 7], pressure supply is directed toan output leg 73 which is communicated with atmosphere, while in thedisabled state, when control pressure is absent, the supply pressureattaches to its preferred output leg 74 which is connected to port 33 atthe set input of counter stage 26 and to control port 66 of flip-flopdevice 61. Regardless of the state of the counter, counter stage 26 isset to produce an output at port 30 to invoke a penalty brakeapplication independent of the continued sequencing of the counter.

ln now describing the operation of the penalty brake control system, letit be assumed that the pure fluid circuit elements are in an activecondition by reason of regulated low-fluid pressure suitable foroperation of such elements being provided at their power input from asource of high-fluid pressure stored in the locomotive main reservoirs.Where these pure fluid elements are of the monostable type, thelow-pressure power stream attaches to a preferred output leg in theabsence of a pressure state control signal, switching to the oppositeoutput leg when a pressure state control signal is presented; wherethese elements are of the bistable class, the power stream remainsattached, in the absence ofa control signal, to the output leg to whichit was last attached, switching to the opposite output leg when thepressure state control signal is reversed from its previous input. Alsoprovided is a regulated source of high-fluid pressure supply forcharging volume 45 and 69 associated with push button valve 44 andelectromagnet valve 68, respectively, it being understood that fluidpressure stored in the locomotive main reservoir also provides thesource of regulated high-fluid pressure. In further establishingconditions under which the circuit functions are initiated, binarycounter 21 is driven by a square wave clock pulse generated at theconnected output of oscillator 22 whereby the input signal effective atthe first counter stage 23 is halved at its output with each succeedingstage 24, 25 and 26 further halving the input signal from the output ofthe previous stage. The counter 21 thus converts the oscillator clockpulse into binary code which provides the option of selecting differentones of, or combinations of outputs to vary timing and sequencing of thewarning and penalty signals to be derived therefrom.

Until the counter sequence, which controls the safety control portion ofthe system, reaches its final or penalty stage 26, output port 30thereof remains in a depressurized state in which a pressure statesignal is absent from control port 40 of flip-flop 39. Assumingflip-flop 39 has been previously reset from its penalty state in which apressure state signal occurred at output leg 41 thereof, as will behereinafter explained, output leg 41 is depressurized such that apressure state signal is absent at control port 20 of interface 4.Consequently, supply pressure at the power input of the OR-gate portion12 assumes its preferred path in which output leg 18 is pressurized toposition the actuator piston (not shown) in the high-pressure portion 11such that its rotor (also not shown) is moved to connect a source ofhigh-fluid pressure effective at port 13 to output 14 and to vent output15 connected to pilot operator 3 of interlock valve 1. Fluid pressure atoutput 14 is connected to pilot operator 2 of interlock valve 1 which isaccordingly forced to a normal position wherein connections are made, asindicated in the left-hand envelope of the valve diagrammatic, toregister communication of fluid pressure effective in line 6 with theequalizing reservoir control volume 5 which is appropriately cut offfrom vented volume 7. Being well established in the airbrake art, it isunderstood that supply pressure effective in line 6 is under control ofthe operator whereby his selective movement of the locomotive automaticbrake valve handle between release and service positions proportionallyvaries the fluid pressure supplied via line 6 and which is effective inthe equalizing reservoir control volume 5 for corresponding brake pipepressure adjustment throughout the train for control of the brakes. Withthe locomotive brake valve device in release position, supply pressureis maintained effective in line 6 at a predetermined maximum value tocharge the equalizing reservoir control volume 5 by way of the interlockvalve 1, as previously explained, and the automatic brake valve devicefunctions in the well-known manner to accordingly charge brake pipepressure for release of the train brakes so that the train may proceed.

With these initial conditions established, a preferred arrangement ofthe invention, as shown, employs AND-gate 36 to detect a signal from thecounter as evidenced by counter output ports 28 and 29 each producingpressure signals concurrently so that the signal occurs a certain timeduration after the count sequence is initiated. Resetting the counterstages to their initial condition to start the count sequence may beaccomplished in several ways, hereinafter explained in detail, all ofwhich result in pressurization of line 32 leading to the reset controlport 31 of each counter stage. Depending upon the frequency of theoscillator pulse train therefore, the warning whistle 10 may becontrolled to sound a predetermined duration after the counter is reset.Accordingly, AND-gate 36 is enabled by the presence of pressure statesignals at its control ports 34 and 35 whenever the counter proceeds toa count where a pressure state signal occurs at outputs 28 and 29 ofcounter stages 24 and 25 respectively. Consequently, AND- gate 36 isenabled whereby its power stream is diverted from its preferred outputleg 37 to its connected output leg 38 from which control port 20 ofinterface device 9 is pressurized. This consequently results ininterface device 9 being enabled by reason of the power stream of thepilot portion OR gate being diverted from the preferred leg 18, in whichthe power stream is normally stable in the absence of a control signal,to the OR- leg 19 whereby the piston actuator in the high-pressureportion 12 is piloted to a position in which the rotor places port 13 incommunication with output port 17. Until the counter proceedssufficiently to produce a pressure state signal at output 30 of counterstage 26, interface device 4, as above explained, assumes a preferredstate in which high-fluid pressure is ported to output 14. This outputpressure, being connected to port 13 of interface device 9, is suppliedby way of its output 17 to the whistle which is accordingly sounded toapprise the engineman of an impending penalty brake application.

From a cursory examination of the binary code which the counter stagesduplicate, it will be seen that the pressure state condition at outputs28 and 29 of counter stages 24 and 25 remain until output 30 of counterstage 26 is pressurized to assure that the whistle continues to sounduntil the counter is either reset or the penalty situation is imposed.

The institution of any one of three functions is sufficient to reset thecounter; namely, manual acknowledgement by the engineman by control ofpush button valve device 44, or by movement of the locomotive brakevalve into suppression position (which automatically causes a fullservice brake application), or by the presence of approximately 25p.s.i. brake cylinder pressure effective on the locomotive such as, forexample, by making an automatic or an independent brake application. I

Volume 45 associated with push button valve 44 is normally charged byway of the valve portion thereof from a high-pressure source. Depressingthe push button operator of valve 44 results in supply pressure beingcut off from volume 45 which is accordingly connected by valving to line32 into which the volume pressure drives a pressure signal which iseffective at reset ports 31 of each counter stage to recycle thecounter, thereby preventing the counter from proceeding to its penaltystage 26. Since the push button operator of valve 44 must be released toreestablish charging of volume 45, it will be apparent that deviousattempts to defeat the periodic acknowledgement function required toforestall the penalty by permanently maintaining a weight on the pushbutton cannot be achieved by reason of the fact that the pressure inline 32 is continually being dissipated at vent ports provided in thepure fluid elements comprising the counter 21, thus assuring that thecounter reset signal will eventually disappear. Also, since each counterstage has inherent memory, it will be apparent that only a momentaryactuation of the push button operator is necessary to effectivelyrecycle the counter, thus relieving the demand upon the engineman tocontinually maintain contact with a safety control valve.

Also provided to pressurize line 32 when either a predetermined amountof locomotive brake cylinder pressure is effective or the locomotivebrake valve is moved to suppression position is pure fluid OR-gate 46.Control port 47 of OR-gate 46 senses brake cylinder pressure by way of arestrictor which drops the pressure linearly to fluidic levels so thatwhen approximately 25 p.s.i. locomotive brake cylinder pressure exists,control pressure at port 47 is sufficient to switch the power streamfrom its preferred output leg 49 to output leg 48 which is connected toline 32, thus resetting the counter.

Pure fluid bistable device 52 is normally conditioned, by reason of thelocomotive brake valve being in release position, and a pressure statesignal being thus provided at control port 54 such that its power streamis diverted to output leg 55 to which is attached in the absence of apressure state signal at opposing control port 51. Movement of the brakevalve out of release position to suppression position results in controlports 51 being pressurized with the corresponding loss of the pressurestate signal at control port 54. Thus, with the brake valve insuppression position, the power stream is switched to output leg 53which it remains attached until the control signals are again reversed.The signal at output leg 53 is connected to a second control port 50 ofthe pure fluid OR-gate 46 which is thereby enabled as previouslydescribed to pressurize line 32 and reset the counter.

In the event the engineman fails for any reason to acknowledge thewarning whistle or conditions are not satisfied to suppress theimpending penalty within a predetermined period and in the prescribedmanner as just described for the purpose of preventing a penaltycondition from occurring, the counter will proceed to produce a pressurestate signal at output 30 of penalty stage 26. At the same time, thepressure state signals at outputs 28 and 29 of counter stages 24 and 25is removed, disabling AND-gate 36 which returns to its preferred statein which its output pressure state signal switches from leg 38 topreferred leg 37. Accordingly, interface device 9 is disabled by theloss of pressure at control port 20 of pilot portion 12 to terminatesounding of the warning whistle 10 due to fluid pressure supplied by wayof interface device 4 being ported to output 16 which is plugged toassure the normal state of interface device 1 by maintainingpressurization of pilot valve 2.

Control port 40 of pure fluid flip-flop 39 is pressurized in thepressure state of output 30 whereby the fluid element power stream isswitched from output leg 42 to output 41 where it remains even after thecontrol signal at port 40 is removed for purposes hereinafter explained.Accordingly, interface device 4, in the penalty state of flip-flop 39,is enabled by the pressure signal effective at control port 20 of itspilot portion 12 whereby the power stream of the fluidic element isswitched from its preferred leg 18 to leg 19. Consequently, thehigh-pressure portion 11 functions to establish fluid pressurecommunication between port 13 and port 15 thereof which pressurizespilot valve 3 while at the same time venting output 14 and pilot valve2. This results in interlock valve device 1 being repositioned to apenalty state to cut off the charging communication between port 6 andthe equalizing reservoir volume which is connected, by way of theinterlock valve spool, to the previously vented reduction limitingreservoir 7 where fluid pressure equalization therebetween occurs toeffect a reduction in equalizing reservoir control pressure and therebyproduces a corresponding automatic train brake application. Inaccordance with pressurization of pilot operator 3 to effect the penaltycondition of interlock valve 1, a power knockout and dynamic brakecutout switch may also be pressurized to cut off the dynamic brakes andshut down the locomotive traction motors.

it is axiomatic from the foregoing that when brake cylinder pressuredevelops at the locomotive to approximately 25 p.s.i., due to a penaltybrake application occurring, the counter stages will be reset through ORgate 46; however, penalty flipflop 39, due to its memory feature, willlatch in the penalty until the proper release procedure is accomplished,as hereinafter explained.

Check valve 8 is provided for the purpose of allowing the engineman theoption of making a further reduction in equalizing reservoir controlpressure effective in control volume 5 after equalization thereof intothe volume 7 incident to effecting a penalty brake application, uponwhich occurrence, normal control of the equalizing reservoir controlpressure by way of the charging control line 6 is cut off by movement ofinterlock device 1 to penalty position. In penalty position of interlockdevice 1, a reduction in equalizing reservoir charging line 6 results inequalizing reservoir control pressure being able to backflow from volume5 by way of the interface spool and volume 7, one-way check valve 8, andagain by way of the spool to follow the reduction effective in line 6,thus allowing the engineman to make a further reduction in equalizingreservoir control pressure (by operating the automatic brake valve)below that normally obtained by equalization into volume 7 whereby aheavier brake application may be,

produced under control of the operator in the event the penalty brakeapplication obtained is not sufficient to bring the train under control.Check valve 8 prevents flow in the opposite direction from theequalizing reservoir charging line 6 to the control volume to prevent apenalty brake application from being released by the engineman except bythe proper procedure as hereinafter explained.

In order to release a penalty imposed brake application and restore thesystem to its normal condition, interlock valve 1 must be reset to itsnormal state to accommodate the supply and release of fluid pressureeffective in the equalizing reservoir control volume 5 in the usualfashion to effect control of the train brakes with the locomotiveautomatic brake valve device. This can only be accomplished by firstmoving the brake valve into suppression position and subsequently backto release position.

Placing the locomotive brake valve in suppression position assures thatthe counter is recycled if not already accomplished to initiate a newcount sequence as previously explained by driving the power stream offlip-flop 52 from output 55 to output 53 which in turn causes OR-gate 46to be enabled to reset the counter stages. This removes the pressurestate signal effective at output 30 of counter stage 26, thusdepressurizing control port 40 of flip-flop 39. Being bistable innature, however, its power stream remains attached to leg 41 to maintainthe penalty state of the system.

Pressurization of output 53 of flip-flop 52 also results inpressurization of control port 64 of flip-flop 61 after a slight delayimposed by delay means 67 while the pressure state control signaleffective at control port 57 of AND-gate 56 in release position of thebrake valve device is being dissipated. The purpose of the delay meansis to allow pressure at port 57 of AND-gate 56 to dissipate beforepressurization of control port 64 of flip-flop 61 is able to divert itspower stream to output 63 and consequently pressurize the second controlport 60 of AND-gate 56 which is thus maintained in its preferred statein which its power stream is connected to output leg 58. Without delaymeans 67, it is apparent that due to the speed of response attributed tofluidic control elements, flip-flop 61 could be enabled before theeffective pressure signal at control port 57 could be dissipated, thusmomentarily presenting pressure state signals at both control ports 57and 60 of AND- gate 56 to enable the device for sufficient duration toinadvertently reset flip-flop 39 from its penalty state.

with removal of the pressure state signal from control port 57 whencontrol port 60 is presented with a pressure state signal in suppressionposition therefore, flip-flop 39 remains conditions by its inherentmemory characteristic to maintain the penalty state of the circuit untilsuch time as the brake valve device is returned to release position.Upon this occurrence, control port 51 of flip-flop device 52 isdepressurized and control port 54 is pressurized whereby the fluid powerstream of flip-flop 52 is switched from output leg 53 back to output leg55 to consequently pressurize control port 57 of AND-gate 56. Sinceflip-flop 61 is bistable in character, its power stream remainsconnected into the output leg 63 even after the pressure state signal isremoved from control port 64 when output 53 of flip-flop 52 isdepressurized whereby pressure state signals occur at both control ports57 and 60 of AND-gate 56. Consequently, AND-gate 56 is enabled whereinits fluid power stream is diverted out of its preferred leg 58 intooutput leg 59 to pressurize control port 43 of flip-flop device 39.Since, as previously explained, control port 40 is depressurized byreason of the counter being reset, the fluid power stream of flip-flop39 is switched from its output leg 41 into leg 42. Accordingly, controlport at the pilot portion 12 of interface device 4 is depressurized andthe pressure state of outputs 14 and 15 is reversed whereby fluidpressure is vented from pilot portion 3 and is reestablished at pilotportion 2 of interlock device 1 which is accordingly moved from itspenalty position to its normal position in which the penalty imposedbrake application is released by reason of equalizing reservoir controlpressure being recharged from line 6 to volume 5 as previouslydescribed.

In order to restore the circuit to its initial condition, the fluidpower stream of bistable flip-flop 61 is driven from output leg 63 toleg 62 by pressurization of control port 65 at the time flip-flop 39 isreset. This results in loss of pressure at control port 60 of AND-gate56 the fluid power stream of which accordingly assumes its preferredoutput leg 58 wherein the device is disabled and the pressure statesignal at control port 43 of flip-flop 39 is dissipated.

The overspeed portion of the system functions to apprise the enginemanof a discrepancy condition existing with respect to the traction motors.Electromagnet valve device 68 detects the motor speed, being normallyconditioned wherein a volume reservoir 69 is charged via theelectromagnet valving by a source of high-fluid pressure. The fluidpressure effective in reservoir 69 is reflected at the control port 72of OR-gate 71 so that under normal conditions, the fluid power stream isdiverted from its preferred leg 74 to its output leg 73. Thus, controlport 66 of flip-flop 61 is vented as is the set control port 33 ofcounter stage 26 whereby the deactivated state of the circuit isassured.

ln the event an overspeed condition occurs, however, electromagnet 68will respond to the discrepancy by interrupting the fluid pressuresupply to volume 69 which is connected to warning whistle 70. The volumeof reservoir 70 is selected so that fluid pressure is expelled by way ofthe whistle which is sounded for a predetermined period until thepressure effective at control port 72 can no longer maintain NOR-gate 71in its disabled state. If the discrepancy condition is not rectifiedwithin this period, the fluid power stream of the NOR-gate 71 assumesits preferred output leg 74 whereby control port 66 of flip-flop 61 andcontrol port 33 of counter stage 26 are pressurized. Consequently,counter stage 26 is set wherein a pressure state signal is produced atoutput 30 thereof to drive flipflop 39 to its penalty state in which apower knockout switch shuts down the traction motors and a penalty brakeapplication is automatically produced as described with respect to thesafety control portion of the system.

In order to release this penalty imposed brake application, the sameprocedure required to release a safety controlled penalty must befollowed provided the overspeed condition has been corrected. Thepurpose of the pressure state signal at control port 66 of flip-flop 61is to prevent the engineman from preconditioning flip-flop 61 to releasethe brakes without first correcting the overspeed condition whichinitiated the penalty. It will be seen that the presence of a pressurestate signal at control port 66 of flip-flop 61 will prevent AND-gate 56from being enabled to reset flip-flop 39 until the overspeed conditionis rectified and NOR-gate 71 is disabled. Upon this occurrence, thepressure state signal at control port 66 is dissipated and the brakeapplication may be released as previously explained by movement of thelocomotive brake valve device first to suppression and subsequently torelease positions. As previously mentioned, the automatic brake valvedevice is designed in such a way that suppression position thereof willcause a full service train brake application, if not already in effect,and is therefore considered a safe condition. Also, due to design of thebrake valve and to the various pressures at which different railroadsoperate, the control system herein described enforces a procedure uponthe operator whereby the brake valve rhust be positively moved intorelease position after first being placed in suppression position beforeinterlock valve 1 is reset to its normal position to assure that norelaxation of the brake application can occur when the brake valve isfirst moved to suppression position.

Having now described the invention, what we claim as new and desire tosecure by Letters Patent, is:

1. A penalty brake control system comprising:

a. a warning indicator device,

b. interlock valve means,

c. multistage counter means,

d. first OR/NOR gate means responsive to a first preselected output ofsaid counter to operate said warning indicator device,

e. second OR/NOR gate means having a first output condition to move saidinterlock means to a normal position and a second output conditiontomove said interlock means to a penalty position, and

f. bistable flip-flop means having a first and second condition andoperable to said first condition in response to a second preselectedoutput of said counter to dispose said second OR/NOR gate means in saidsecond condition a predetermined time duration following the occurrenceof said first preselected output of said counter.

2. A penalty brake control system as recited in claim 1, and furthercomprising a plurality of means for selectively controlling said countermeans to effect a reset condition thereof.

3. A penalty brake control system as recited in claim 2, and furthercomprising means for continuously feeding an operating signal to drivesaid counter.

4. A penalty brake control system as recited in claim 3, wherein saidmeans for continuously feeding an operating signal to drive said countercomprises oscillator means.

5. A penalty brake control system as recited in claim 2, wherein saidplurality of means for controlling said counter to effect a resetcondition thereof comprises:

a. a manually actuated push button valve means to provide a reset signalat said counter,

b. multiinput OR gate means disposed in parallel with said manuallyactuated push button means and having one input adapted for connectionto a locomotive brake cylinder pressure, and

c. a second bistable flip-flop means having one input for connection tothe suppression output of a brake valve device and having acorresponding output for providing a signal at another input of saidmultiinput OR gate means.

6. A penalty brake control system as recited in claim 1, and furthercomprising means for resetting said flip-flop means to said secondcondition.

7. A penalty brake control system as recited in claim 6, wherein saidresetting means comprises means including AND gate means providing areset output in response to a signal at one input of said AND gateproduced by movement ofa brake valve device to one position and to aconcurrent signal at a second input of said AND gate produced bysubsequent movement of the brake valve to a second position.

8. A penalty brake control system as recited in claim 7, wherein saidmeans including said AND gate means further comprises a third flip-flopmeans having a first and second output condition and responsive at oneinput thereof to the output of said second flip-flop means when saidbrake valve device is mounted into said one position to provide anoutput for maintaining a signal at said one input of said AND gate whensaid brake valve device is subsequently moved to said second position.

9. A penalty brake control system as recited in claim 8, wherein saidthird flip-flop means includes a second input responsive to the outputof said first flip-flop when said first flip-flop is in second conditionwhereby said third flip-flop is disposed in said first output condition.

10. A penalty brake control system as recited in claim 8, and furthercomprising:

a. electromagnetic valve means having a first position for communicatinga source of pressure to atmosphere, and having a second position forcommunicating said source of pressure to an output,

b. a second warning signal device actuatable when said electropneumaticvalve means is disposed in said second position,

c. said counter having an additional input which when pressurizedeffects said second preselected output,

d. NOR gate means having a NOR output pressurizable in response to saidsecond position of said electromagnetic valve device, said NOR outputconnected to said additional input. II. A penalty brake control systemas recited in claim 10,

wherein said third flip-flop means includes a third input for disposingsaid third flip-flop in said first condition responsive topressurization of said NOR output of said NOR gate.

12. A penalty brake control system as recited in claim 9, in which saidcounter produces a binary output and AND gate means are interposedbetween said counter and said second OR gate means, said AND gate beingresponsive to the outputs of at least two concurrently existingpreselected outputs comprising said second preselected output of saidcounter.

13. A penalty brake control system, comprising:

a. a binary counter comprised of a plurality of stages of said purefluid devices,

b. said binary counter having:

i. first input means for operating said counter in a cyclic manner inresponse to a signal at said first input means,

ii. second input means for resetting said binary counter to apredetermined count condition only so long as said second input means ispressurized, and

iii. output means for connection to associated apparatus,

0. a reservoir,

d. valve means operative to a first position for communicating saidreservoir to a source of supply, and having a second position forcommunicating said reservoir to said second input means.

1. A penalty brake control system comprising: a. a warning indicatordevice, b. interlock valve means, c. multistage counter means, d. firstOR/NOR gate means responsive to a first preselected output of saidcounter to operate said warning indicator device, e. second OR/NOR gatemeans having a first output condition to move said interlock means to anormal position and a second output condition to move said interlockmeans to a penalty position, and f. bistable flip-flop means having afirst and second condition and operable to said first condition inresponse to a second preselected output of said counter to dispose saidsecond OR/NOR gate means in said second condition a predetermined timeduration following the occurrence of said first preselected output ofsaid counter.
 2. A penalty brake control system as recited in claim 1,and further comprising a plurality of means for selectively controllingsaid counter means to effect a reset condition thereof.
 3. A penaltybrake control system as recited in claim 2, and further comprising meansfor continuously feeding an operating signal to drive said counter.
 4. Apenalty brake control system as recited in claim 3, wherein said meansfor continuously feeding an operating signal to drive said countercomprises oscillator means.
 5. A penalty brake control system as recitedin claim 2, wherein said plurality of means for controlling said counterto effect a reset condition thereof comprises: a. a manually actuatedpush button valve means to provide a reset signal at said counter, b.multiinput OR gate means disposed in parallel with said manuallyactuated push button means and having one input adapted for connectionto a locomotive brake cylinder pressure, and c. a second bistableflip-flop means having one input for connection to the suppressionoutput of a brake valve device and having a corresponding output forproviding a signal at another input of said multiinput ''''OR'''' gatemeans.
 6. A penalty brake control system as recited in claim 1, andfurther comprising means for resetting said flip-flop means to saidsecond condition.
 7. A penalty brake control system as recited in claim6, wherein said resetting means comprises means including AND gate meansproviding a reset output in response to a signal at one input of saidAND gate produced by movement of a brake valve device to one positionand to a concurrent signal at a second input of said AND gate producedby subsequent movement of the brake valve to a second position.
 8. Apenalty brake control system as recited in claim 7, wherein said meansincluding said AND gate means further comprises a third flip-flop meanshaving a first and second output condition and responsive at one inputthereof to the output of said second flip-flop means when said brakevalve device is mounted into said one position to provide an output formaintaining a signal at said one input of said AND gate when said brakevalve device is subsequently moved to said second position.
 9. A penaltybrake control system as recited in claim 8, wherein said third flip-flopmeans includes a second input responsive to the output of said firstflip-flop when said first flip-flop is in second condition whereby saidthird flip-flop is disposed in said first output condition.
 10. Apenalty brake control system as recited in claim 8, and furthercomprising: a. electromagnetic valve means having a first position forcommunicating a source of pressure to atmosphere, and having a secondposition for communicating said source of pressure to an output, b. asecond warning signal device actuable when said electropneumatic Valvemeans is disposed in said second position, c. said counter having anadditional input which when pressurized effects said second preselectedoutput, d. NOR gate means having a NOR output pressurizable in responseto said second position of said electromagnetic valve device, said NORoutput connected to said additional input.
 11. A penalty brake controlsystem as recited in claim 10, wherein said third flip-flop meansincludes a third input for disposing said third flip-flop in said firstcondition responsive to pressurization of said NOR output of said NORgate.
 12. A penalty brake control system as recited in claim 9, in whichsaid counter produces a binary output and AND gate means are interposedbetween said counter and said second OR gate means, said AND gate beingresponsive to the outputs of at least two concurrently existingpreselected outputs comprising said second preselected output of saidcounter.
 13. A penalty brake control system, comprising: a. a binarycounter comprised of a plurality of stages of said pure fluid devices,b. said binary counter having: i. first input means for operating saidcounter in a cyclic manner in response to a signal at said first inputmeans, ii. second input means for resetting said binary counter to apredetermined count condition only so long as said second input means ispressurized, and iii. output means for connection to associatedapparatus, c. a reservoir, d. valve means operative to a first positionfor communicating said reservoir to a source of supply, and having asecond position for communicating said reservoir to said second inputmeans.